Navigation among multiple breast ultrasound volumes

ABSTRACT

Navigation among breast ultrasound volumes derived from different volumetric ultrasonic scans of a same breast is described. On a display of a breast ultrasound workstation, a first image derived from a first ultrasonic volume is displayed. A user selection of a source region of interest (ROI) in the first image is received. A destination ROI within a second ultrasonic volume is identified that at least roughly corresponds to a same locality of tissue in the breast as the source ROI. A second image derived from the second ultrasonic volume and including the destination ROI is displayed, the destination ROI being highlighted.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/684,622, filed May 24, 2005, which is incorporated by referenceherein.

FIELD

This patent specification relates to medical ultrasound imaging. Moreparticularly, this patent specification relates to processing and/ordisplay of breast ultrasound information for breast cancer screeningand/or diagnosis purposes.

BACKGROUND

The subject matter of this patent specification relates to theprocessing and display of breast ultrasound information as described,for example, in the commonly assigned US 2003/0007598A1 and US2003/0212327A1, each of which is incorporated by reference herein. Thesubject matter of this patent specification also relates to theprocessing and display of breast ultrasound information acquiredaccording to the commonly assigned U.S. Prov. Ser. No. 60/629,007 filedNov. 17, 2004, and U.S. Ser. No. 10/997,293 filed Nov. 23, 2005, each ofwhich is incorporated by reference herein.

In one or more of the above-referenced disclosures, there are presentedconvenient schemes for viewer navigation between (a) thick-slice imagesgenerated from a breast volume and (b) planar (“single-slice”) imagesfor that breast volume, as well as navigation in the other directionfrom the planar images to the thick-slice images. Thus, for example, aviewer can click on a region of interest (ROI) in one of the thick-sliceimages, and the display will automatically show the appropriatecorresponding planar images that pass through that ROI in the breastvolume, and will also place markers thereon corresponding to that ROI.This is a valuable capability because the viewer is provided withmultiple image presentations of the ROI without having to scan throughthe various images for corresponding ROIs, which can be a time-consumingand stamina-reducing task. Rather, the viewer simply clicks on the ROIon the image being examined, and that location is automatically“navigated to” and highlighted by the workstation display system in theother views. Generally speaking, such automated navigation between viewsis not problematic when there is a single ultrasound volume for eachbreast, because the absolute location of the ROI within the breastbecomes known as soon as the viewer clicks on the selected point.

It has been found desirable in many instances to obtain multiplevolumetric ultrasound scans of the same breast during the same session.With reference to FIGS. 28-32 infra, the multiple volumetric ultrasoundscans can be head-on scans taken at differing positions or orientations,each of the scans being taken while a taut surface compresses the breastin a generally chestward direction and an ultrasound probe is sweptthereacross. In other cases, there may be scans taken while the breastis compressed along differing mammographic planes such as the CC or MLOplanes, as iconically represented, for example, by the body marker icons1202, 1204, and 1206 of FIG. 12 infra.

The use of multiple volumetric scans can overcome certain disadvantagesassociated with of single-volumetric scan scenarios. In particular, forany particular volumetric ultrasound scan, there can be shadowing orother obfuscations of interesting tissue structures because of thepresence of other tissue structures that are “in the way” during thescanning process. When there is only a single volumetric scan available,there is generally no way for the viewer to know what structures arebehind or underneath the obfuscating structures. However, when there aremultiple volumetric ultrasound scans available that were taken fromdifferent positions/directions, the viewer can consult a secondultrasound volume to better see the obfuscated structure.

It would be desirable to streamline the process of viewing additionalultrasonic volumes by providing for automated navigation between a firstultrasonic volume of a breast acquired during a first volumetric scanthereof and a second ultrasonic volume of the same breast taken during asecond volumetric scan thereof, the first and second volumetric scanshaving been taken at differing positions and/or orientations.

SUMMARY

A method, system, and associated computer program product is providedfor automated navigation between a first ultrasonic volume of a breastacquired during a first volumetric scan thereof and a second ultrasonicvolume of the same breast taken during a second volumetric scan thereof.On a display of a breast ultrasound workstation, a first image isdisplayed, the first image being derived from the first ultrasonicvolume and comprising one of (i) a thick-slice image representing thefirst ultrasonic volume within a slab-like subvolume thereof, and (ii) aplanar image representing the first ultrasonic volume along a planetherethrough. A user selection of a source region of interest (ROI) inthe first image is received. The source ROI is mapped from the firstimage into the first ultrasonic volume according to the known positionof the slab-like subvolume or plane within the first ultrasonic volume.The source ROI is then mapped from within the first ultrasonic volumeinto a corresponding destination ROI within the second ultrasonic volumeof the breast. The destination ROI is then mapped onto a second image,the second image comprising one of (i) a thick-slice image representingthe second ultrasonic volume within a slab-like subvolume thereof, and(ii) a planar image representing the second ultrasonic volume along aplane therethrough, this mapping being in accordance with a knownposition of the slab-like subvolume or plane within the secondultrasonic volume. The second image is displayed to the viewer with theposition of the destination ROI therein being highlighted.

In one preferred embodiment, the mapping from the source ROI within thefirst ultrasonic volume into the corresponding destination ROI withinthe second ultrasonic volume first comprises identifying a nipplelocation of the breast in each of the first and second ultrasonicvolumes thereof. A projected location of the source ROI onto a firstcoronal reference plane passing through the nipple location within thefirst ultrasonic volume is then identified. A Cartesian offset betweenthe projected source ROI location and the nipple location on the firstcoronal reference plane is then determined. That Cartesian offset isthen transferred to a second coronal reference plane to identify atransferred offset point thereon, the second coronal reference planepassing through the nipple location within the second ultrasonic volume.The transferred offset point is then backprojected from the secondcoronal reference plane into the second ultrasonic volume.

In another preferred embodiment, accommodations are made for compressionof the breast along an anti-coronal plane (i.e., along a planeperpendicular to the coronal plane, which would include CC, MLO, andLAT, for example) during one or both of the volumetric scans. Inparticular, where the breast was so compressed during the first scan orthe second scan (but not both), the transferred point on the secondcoronal reference plane is modified according to an elastic mappingbetween a coronal projection of the anti-coronally-compressed breastonto a coronal projection of the non-anti-coronally-compressed breast.If the breast was so compressed for both volumetric scans, the breastbeing compressed along a first anti-coronal plane during the firstvolumetric scan thereof and compressed along a second anti-coronal planeduring the second volumetric scan thereof, the transferred point on thesecond coronal reference plane is modified according to an elasticmapping between a coronal projection of the breast as compressed alongthe first anti-coronal plane and a coronal projection of the breast ascompressed along the second anti-coronal plane. The elastic mapping isdetermined at least in part according to a measured compression forceand a distance between compression plates during breast compressionalong the anti-coronal plane.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a conceptual diagram of a breast cancer screeningand/or diagnosis system according to a preferred embodiment;

FIG. 2 illustrates a perspective view of a breast volume and slab-likesubvolumes thereof substantially parallel to a coronal plane, and anarray of two-dimensional coronal thick-slice images correspondingthereto;

FIG. 3 illustrates a method for processing and displaying breastultrasound information according to a preferred embodiment;

FIG. 4 illustrates a front view of a breast, a front view of slab-likesubvolumes thereof substantially parallel to standard x-ray mammogramplanes, and arrays of standard-plane thick-slice images correspondingthereto for display in conjunction with the coronal thick-slice imagesof FIG. 2 according to a preferred embodiment;

FIG. 5 illustrates a user display according to a preferred embodiment;

FIGS. 6A and 6B illustrate a side view of a breast and an example ofdifferent slab-like coronal subvolume thickness schemes according to apreferred embodiment;

FIG. 7 illustrates a method for processing and displaying breastultrasound information according to a preferred embodiment;

FIG. 8 illustrates a user display according to a preferred embodiment;

FIG. 9 illustrates a user display according to a preferred embodiment;

FIG. 10 illustrates a breast ultrasound display according to a preferredembodiment;

FIG. 11 illustrates a menu bar of a breast ultrasound display accordingto a preferred embodiment;

FIGS. 12 and 13 illustrate body marker icons according to a preferredembodiment;

FIG. 14 illustrates a thick-slice image and planar views according to apreferred embodiment;

FIG. 15 illustrates a bilateral comparison array of thick-slice images,corresponding body marker icons, and a display control button accordingto a preferred embodiment;

FIG. 16 illustrates a bilateral comparison view of thick-slice imagesand corresponding body marker icons according to a preferred embodiment;

FIG. 17 illustrates an array of thick-slice images with nipple markers,a body marker icon, and a frontal breast icon according to a preferredembodiment;

FIG. 18 illustrates a thick-slice image and planar images with displayedbookmarks, a body marker icon, a frontal breast icon, a marker displaybutton, and marker navigation buttons according to a preferredembodiment;

FIG. 19 illustrates an array of thick-slice images with viewer-shiftednipple markers, a body marker icon, and a frontal breast icon accordingto a preferred embodiment;

FIG. 20 illustrates an array of thick-slice images with nipple markersand bookmarks, a marker display button, and marker navigation buttonsaccording to a preferred embodiment;

FIGS. 21 and 22 illustrate breast ultrasound volume acquisition,processing, and display according to one or more preferred embodiments;

FIG. 23 illustrates a bilateral comparison array view of thick-sliceimages and corresponding body marker icons according to a preferredembodiment;

FIG. 24 illustrates examples of virtual probe reconstruction planesaccording to a preferred embodiment;

FIG. 25 illustrates a full-breast composite thick-slice image, a bodymarker icon, and a frontal breast icon according to a preferredembodiment;

FIG. 26 illustrates a volume-rendered breast ultrasound volume withsurface-rendered computer-assisted diagnosis (CAD) detections thereinaccording to a preferred embodiment.

FIG. 28 illustrates a diagram of head-on breast ultrasound scanningaccording to a preferred embodiment;

FIG. 29 illustrates a diagram of lateral frontal breast ultrasoundscanning according to a preferred embodiment;

FIG. 30 illustrates a diagram of medial frontal breast ultrasoundscanning according to a preferred embodiment;

FIG. 31 illustrates a diagram of inferior frontal breast ultrasoundscanning according to a preferred embodiment;

FIG. 32 illustrates a diagram of superior frontal breast ultrasoundscanning according to a preferred embodiment;

FIG. 33 illustrates thick-slice images from first and second breastultrasound volumes and a region of interest (ROI) to be mapped from thefirst breast ultrasound volume to the second breast ultrasound volumeaccording to a preferred embodiment;

FIG. 34 illustrates a conceptual view of projection of a Cartesianoffset from a nipple location in a first breast ultrasound volume to acoronal reference plane according to a preferred embodiment;

FIGS. 35-36 illustrate transfer of (a) Cartesian offset from the nipple,and (b) depth from the skinline/compressive surface from the firstbreast ultrasound volume to the second breast ultrasound volumeaccording to a preferred embodiment;

FIG. 37 illustrates the thick-slice images of FIG. 33 including ahighlighted destination ROI according to a preferred embodiment; and

FIG. 38 illustrates a conceptual view of ROI mapping in whichaccommodations are made for compression of the breast along one or moreanti-coronal planes.

DESCRIPTION

FIG. 1 illustrates a conceptual diagram of a breast cancer screeningand/or diagnosis system according to a preferred embodiment. The breastof a patient 101 is ultrasonically scanned by an automated scanningapparatus while the patient is in a prone position (device 102), anupright position (device 102′), a supine position (device 102″) or otherposition (not shown). By reducing the required ultrasonic penetrationdepth to the chest wall, scanning of a chestwardly compressed breast canoccur at higher frequencies, e.g., 10-20 MHz, which can yield very highresolution images sufficient to facilitate detection ofmicrocalcifications or other structures on the order of 1 mm near thechest wall. However, it is to be appreciated that the scope of thepreferred embodiments is not limited to a chestwardly-compressedscenario, with breast ultrasound information processing and displayaccording to the preferred embodiments being generally useful with anyscanning system from which a three-dimensional volumetric representationof a sonographic property of the breast can be derived.

Breast scans are obtained under the control of a scanning engine andworkstation 104 including, for example, a monitor 106, keyboard 108, amouse 110, and a scanning engine (not shown). During or after thescanning process, the ultrasound scan data is provided across a computernetwork 112 to an ultrasound server 114 that processes and generatesdisplay information according to the functionalities described herein.The ultrasound server 114 may perform other HIS/RIS (hospitalinformation system/radiology information system) activities such asarchiving, scheduling, etc. It is to be appreciated that the processingof the ultrasound scan data may be performed by any of a variety ofdifferent computing devices coupled to the computer network 112 invarious combinations without departing from the scope of the preferredembodiments.

According to a preferred embodiment, a viewing workstation 122 isprovided that displays an array 124 of coronal thick-slice images to aclinician 121, each coronal thick-slice image representing a sonographicproperty of the breast within a slab-like subvolume thereofsubstantially parallel to a coronal plane. As used herein, the term“clinician” generically refers to a medical professional, such as aradiologist, or other person that analyzes medical images and makesclinical determinations therefrom, it being understood that such personmight be titled differently, or might have varying qualifications,depending on the country or locality of their particular medicalenvironment. In another preferred embodiment, as shown in FIG. 1, one ormore standard-plane thick slice image arrays are displayed to theclinician 121, such as a craniocaudal (CC) thick-slice image array 126and a mediolateral oblique (MLO) thick-slice image array 128.

In another preferred embodiment (not shown), the clinician is alsoprovided with the ability to view individual planar ultrasound slices(along sagittal, axial, coronal, or other cut-planes through thethree-dimensional breast volume) as desired. An example of one desirableplanar ultrasound display and navigation scheme is provided in thecommonly assigned US2003/0212327A1, supra, and in other preferredembodiments described herein.

FIG. 2 illustrates a perspective view of a breast volume 201 and coronalslab-like subvolumes 204-210 thereof substantially parallel to a coronalplane, along with the array 124 of two-dimensional coronal thick-sliceimages generated therefrom according to a preferred embodiment. Thecoronal slab-like subvolumes 204-210, which are separated by planes 202,correspond to the coronal thick-slice images 212-218, respectively.Generally speaking, the coronal slab-like subvolumes nearer to the chestwall (e.g., 204-206) have a larger cross-section in the coronal planethan the slab-like subvolumes nearer to the nipple 203 (e.g., 208-210).As used herein, coronal slab-like subvolumes refer generally toslab-like subvolumes within the breast that are roughly parallel to thechest wall of the patient. The coronal slab-like subvolumes 204-210typically have a thickness in the range of 2-20 mm. Optionally, thecoronal slab-like subvolumes can be gently contoured to more closelyfollow the contours of the chest wall. In such cases, the coronalslab-like subvolumes would have surfaces roughly reminiscent of asection of a hyperboloid, or roughly reminiscent of a potato chip.

Generally speaking, a coronal thick-slice image comprises an integrationof a plurality of individual ultrasound slices lying within a coronalslab-like subvolume. Thus, for example, where the coronal slab-likesubvolume 204 is represented by a three-dimensional voxel array V(x,y,z)of scalar values, the corresponding coronal thick-slice image 212 wouldbe a two-dimensional pixel array P_(COR)(x,y) of scalar values. In onepreferred embodiment, each pixel value P_(COR)(x,y) is simply computedas an arithmetic average along the corresponding voxel column at (x,y)having the voxel values V(x,y,z₀), V(x,y,z₁), V(x,y,z₂), . . . ,V(x,y,z_(N)), where N is the number of individual ultrasound sliceslying in the coronal slab-like subvolume. For clarity of description,the voxel column at (x,y) having the voxel values V(x,y,z₀), V(x,y,z₁),V(x,y,z₂), . . . , V(x,y,z_(N)) is expressed herein as V_(xy)(z).

Techniques for integrating the component ultrasound slices into thecoronal thick-slice images P_(COR)(X,y) according to the preferredembodiments include arithmetic averaging, geometric averaging,reciprocal averaging, exponential averaging, and other averagingmethods, in each case including both weighted and unweighted averagingtechniques. Other suitable integration methods may be based onstatistical properties of the population of component ultrasound slicesat common locations, such as maximum value, minimum value, mean,variance, or other statistical algorithms.

Preferably, the coronal slab-like subvolumes have a thickness related tothe size of the lesions to be detected. At an upper end, a largerthickness of 20 mm, for example, may be used if it is desirable tooverlook most of the breast details and direct the user's attention tolarger features on the order 10 mm in size. At a lower end, a smallerthickness of 2 mm, for example, may be used if it is desirable to viewsmall structures, such as microcalcifications, on the order of 1 mm insize. Thicknesses in the range of 4 mm-10 mm are likely to be suitablefor most breast cancer screening purposes.

In other preferred embodiments, the pixel value P_(COR)(x,y) may becomputed according to an algorithm that processes a neighborhood ofvoxel columns around the voxel column V_(xy)(z), the algorithm beingdesigned to result in coronal thick-slice images that emphasize lesionsof a predetermined size range. In one such preferred embodiment, theintegration method comprises weighting the voxels of the correspondingvoxel column by a weighting vector and then summing the results, theweighting vector being computed according to neighborhoodcharacteristics around that voxel column. This can be summarized by Eq.(1) below: $\begin{matrix}{{P_{COR}\left( {x,y} \right)} = {{{FUNC}\left\{ {V_{xy}(z)} \right\}} = {\sum\limits_{n = 1}^{N}{{W_{xy}(n)}{V_{xy}\left( z_{n} \right)}}}}} & \left\{ 1 \right\}\end{matrix}$

Using known three-dimensional segmentation and computer-aided detection(CAD) techniques, the locations and sizes of lesions in the coronalthick-slice volume are identified, either directly or by way of amapping from the overall three-dimensional breast volume. Any of avariety of known three-dimensional segmentation and/or CAD algorithmscan be used such as those discussed in U.S. Pat. No. 6,317,617 toGilhuijs, Giger, and Bick, which is incorporated by reference herein. Inone preferred embodiment, for a given voxel column, the weighting vectorW_(xy)(n) comprises peaks at locations lying within the lesions andvalleys elsewhere, thus causing the resulting coronal thick-slice imageto emphasize mass lesions in the output. In another preferredembodiment, the weighting vector W_(xy)(n) can be computed as describedin the commonly assigned WO 02/101303A1, which is incorporated byreference herein. The CAD-detected abnormalities can includemicrocalcifications, suspicious masses, and/or other known breastabnormalities.

FIG. 3 illustrates a method for processing and displaying breastultrasound information according to a preferred embodiment. At step 302,volumetric ultrasound scans of the chestwardly-compressed breast areacquired, either in real-time as the breast is being scanned, or in anoff-line manner as from a database or archive of previously-acquiredimages. At step, 304, coronal thick-slice images are computedcorresponding to slab-like subvolumes of the chestwardly-compressedbreast substantially parallel to coronal plane. At step 306, the arrayof coronal thick-slice images is displayed on a user display, preferablyin a side-by-side manner. However, a variety of different spatialarrangements of the coronal thick-slice images are within the scope ofthe preferred embodiments. For example, the array may be presented incircular or matrix fashion. In one preferred embodiment, all of thecoronal thick-slice images collectively corresponding to the entirebreast volume are simultaneously displayed to the viewer, so that thewhole breast is effectively shown at the same time, thereby facilitatingclinical workflow efficiency. In another preferred embodiment, thecoronal thick-slice images can be progressively displayed at successivetime intervals, either automatically or responsive to user controls.

According to one preferred embodiment, at step 308 craniocaudal (CC)thick-slice images, which are one type of standard-plane thick-sliceimage, are computed corresponding to slab-like subvolumes of thechestwardly-compressed breast substantially parallel to an axial plane,which corresponds to the CC view. At step 310 mediolateral oblique (MLO)thick-slice images, which are another type of standard-plane thick-sliceimage, are computed corresponding to slab-like subvolumes of thechestwardly-compressed breast substantially parallel to an MLO plane. Atstep 312, the arrays of CC and MLO thick-slice images are presented onthe user display.

FIG. 4 illustrates a conceptual front view of the breast 201 upon whichare drawn (i) front-view outlines of slab-like subvolumes A-Hcorresponding to CC slab-like subvolumes, and (ii) front-view outlinesof slab-like subvolumes I-VI corresponding to MLO slab-like subvolumes.Also shown in FIG. 4 is a portion of the viewing workstation 122illustrating the CC thick-slice image array 126 and the MLO thick-sliceimage array 128 with indicators mapping them into the slab-likesubvolumes A-H and I-VI, respectively. The CC and MLO thick-slice imagearrays can be generated from the three-dimensional breast volume in amanner analogous to that described in WO 02/101303A1, supra. As known inthe art, the MLO plane is usually about 55 degrees away from the CCplane. It is to be appreciated, however, that a variety of angles forthe MLO plane can be used without departing from the scope of thepreferred embodiments, including 90 degrees (in which case itcorresponds to the mediolateral “ML” view) or greater.

Referring again to FIG. 3, according to one preferred embodiment,standard CC and MLO x-ray mammogram views of the breast are displayed atsteps 314 and 316, respectively. FIG. 5 illustrates a viewingworkstation 502 similar to the viewing workstation 122, supra, with theaddition of CC and MLO x-ray mammogram images 504 and 506, respectively,which can further facilitate screening and diagnosis throughback-and-forth viewing of interesting areas. The CC and MLO x-raymammogram images 504 and 506 are preferably in digitized form forpractical reasons, although it is within the scope of the preferredembodiments for these to be film-based x-ray mammograms on a light-boxbackground.

FIGS. 6A and 6B illustrate side views of a breast 201 next to a chestwall 602 for the purpose of describing coronal slab-like subvolumethickness schemes according to the preferred embodiments. In thepreferred embodiment of FIG. 6A, the thicknesses of coronal slab-likesubvolumes 1-5 are substantially equal. However, in the preferredembodiment of FIG. 6B, there is a graded or phased approach to thethicknesses of coronal slab-like subvolumes 1-5. More particularly, theinner subvolumes 1-2 are thinner than the outer subvolumes 4-5. Thus, anaverage thickness of a first subset of said slab-like subvolumes locatedcloser to the chest wall is less than an average thickness of a secondsubset of said slab-like subvolumes located farther from the chest wall.

The graded or phased approach of FIG. 6B has been found advantageousbecause a large percentage of breast lesions are nearby to the chestwall, and so a more precise viewing of these tissues (i.e., approachingthe precision of conventional thin-slice ultrasound images) iswarranted. At the same time, however, it is still desirable to avoid“too much information” on the user display, and so thicker subvolumesfor the regions farther away from the chest wall are used to keep theoverall number of required images at manageable levels.

FIG. 7 illustrates a method for processing and displaying breastultrasound information according to a preferred embodiment. At step 702,the three-dimensional data volume is processed according to at least onecomputer-aided detection (CAD) algorithm to detect anatomicalabnormalities therein. These CAD algorithms can be the same as usedsupra for enhancing the visual appearance of lesions in the thick-sliceimages, or alternatively can be different and/or additional CADalgorithms. At step 704, the detected lesions in the three-dimensionaldata volume are mapped into their corresponding coronal thick-sliceimages. The detected lesions are also mapped into their corresponding CCand/or MLO thick-slice images if present. At step 706, annotations aresuperimposed on the corresponding coronal, CC, and/or MLO thick-sliceimages according to type and location of detected anatomicalabnormality.

FIG. 8 illustrates a viewing workstation 802 according to a preferredembodiment, which is similar to the viewing workstation 122 but alsoincludes CAD annotations on the coronal, CC, and MLO thick-slice images.The CAD annotations are placed according to type and location ofdetected anatomical abnormality. In the example of FIG. 8, aCAD-detected suspicious microcalcification cluster is denoted bytriangles 804 a, 804 b, and 804 c on the appropriate members of thecoronal, CC, and MLO thick-slice image arrays, respectively. ACAD-detected suspicious mass is denoted by asterisk-shaped markers 806a, 806 b, and 806 c on the appropriate members of the coronal, CC, andMLO thick-slice image arrays, respectively. 100631 FIG. 9 illustrates aportion 902 of a viewing workstation according to a preferredembodiment, including an array 904 of coronal thick-slice images. It hasbeen found useful to identify the x-y location of the nipple relative tothe coronal thick-slice images on the user display, as indicated by thenipple markers 906. For example, it will not always be the case that thenipple will be at the center of each coronal thick-slice image, foranatomical reasons as well as the fact that there may be variations inthe angle of attack of the chestward compressive force on the breast.These variations in the angle of attack may be unintentional, as in thecase of imperfect patient positioning, or may be intentional, as in thecase where a particular area of the breast (e.g., the upper innerquadrant) may be of concern in a follow-up scan. The position of thenipple can be determined using CAD algorithms on the three-dimensionaldata volume based on nipple shadow effects. Alternatively, the nippleposition may be identified manually by the technician at the time ofscanning, e.g., by ensuring that the nipple falls on a predeterminedpoint on the compression plate, or by interacting with the scanningsystem based on a quick exploratory sweep across the breast by theprobe, or by manually positioning the probe at the nipple location andpressing a nipple identification button, or by any of a variety of othermanual nipple identification schemes.

FIG. 10 illustrates a breast ultrasound display 1002 according to apreferred embodiment, generally comprising an image area 1004 and a menubar 1006. In the particular display of FIG. 10, an array of sixthick-slice images 1008 a-1008 e is displayed, as well as two planarultrasound images 1010 a-1010 b. The display 1002 can be used in theviewing workstation 122 of FIG. 1, supra. The display 1002 can be usedas part of a multi-modality PACS workstation, as a stand-alone device,and/or in conjunction with an x-ray mammography softcopy or hardcopy(i.e., lightbox) viewing station.

FIG. 11 illustrates a closer view of the menu bar 1006 comprising avariety of controls and information displays relating to the image area1004. Menu bar 1006 comprises a body marker icon 1102, cine control(soft) buttons 1103, a marker display button 1104, marker navigationbuttons 1106, a bilateral comparison control button 1108, a somogrambutton 1110, an invert button 1112, and a variety of file controlbuttons 1114. A designation of “/N” (N=2, 3, . . . ) on a view-relatedone of the file control buttons 1114 indicates that N sets of data areavailable for display for that view, e.g., N scans were takencorresponding to that view. The number preceding the “/N” denotes whichof those sets is being displayed.

The cine control buttons 1103 allow the viewer to start a slice-by-sliceultrasound view cine loop sequence of the current breast view. It willstart at-the current cursor location, moving toward a first edge of thebreast volume. It will delay there for a short period of time, thenrestart at the other edge of the breast volume. Pressing any button ormoving the mouse while the cine is active will stop the cine loop,leaving the cursor at its most recent cine position. The invert button1112 enables toggling of the thick-slice images between two differentgrayscale mapping modes, one for a generally white-on-black image mode,and another for a generally black-on-white image mode.

The bilateral comparison control button 1108 allows the viewer todynamically toggle between displaying a bilateral comparison viewformat, as described further infra with respect to FIGS. 15-16 and FIGS.19-20, or thick-slice views of a single breast. The somogram button 1110allows the viewer to toggle between a first configuration in which onlyplanar views are shown, a second configuration in which only thick-sliceimages are shown, and a third configuration in which combinations ofthick-slice images and planar images are shown.

The marker display button 1104 allows the viewer to toggle between (i)non-annotated versions of the displayed images, and (ii) versionsshowing bookmarks as described further infra. The marker navigationbuttons 1106 allow the viewer to perform bookmark-centric navigationwherein, upon selection, there is automatically displayed acorresponding one of the thick-slice images associated with a locationof a next bookmark (forward) or prior bookmark (backward), as well as aone or more planar ultrasound images corresponding to that location. Thebookmarks themselves may be entered by the viewer using a simpleright-click and pull-down menu process, although the scope of thepreferred embodiments is not so limited. By way of example, bookmarksmay be provided by other users, automatically generated according toarchived data, or by any of a variety of other processes.

Although not shown in FIG. 11, in another preferred embodiment there isprovided a CAD display button and CAD navigation buttons providingsimilar navigational functionality as the marker display button 1104 andthe marker navigation buttons 1106. In still another preferredembodiment, a nipple marker display button is provided for togglingbetween displaying nipple markers, described further infra, and notdisplaying nipple markers.

Body marker icon 1102 is automatically generated and provides fastcommunication of several different aspects of the images beingdisplayed. A text section 1116 communicates a compression angle (fornon-frontal, i.e., non-coronal, compression planes such as CC, MLO, LAT,etc.), a separation distance between compression plates (again fornon-frontal compression planes), and a compression force used during thescans. The body marker icon 1102 further displays a compression plane1117 against which the breast was compressed, a thick-slice depth marker1118 corresponding to the depth of the displayed thick-slice image (whenone thick-slice image is displayed), and a plane marker 1120corresponding to a planar ultrasound image being displayed, ifapplicable.

FIG. 12 illustrates body marker icons for various non-frontalcompression scenarios. The body marker icon 1202 corresponds to a LATview of the right breast, the body marker icon 1204 corresponds to a CCview of the right breast, and the body marker icon 1206 corresponds toan MLO view of the left breast.

FIG. 13 illustrates body marker icons 1302, 1304, and 1306 for variousfrontal compression scenarios, each comprising a probe sweep indicator(e.g., 1303) indicating a trajectory and orientation of the linearscanning probe that scanned the breast. The body marker icon 1302corresponds to a frontal scan of a medial side of the left breast in theinferior-to-superior direction, the body marker icon 1306 corresponds toa frontal scan of a medial side of the right breast in a direction closeto the inferior-to-superior direction, and the body marker icon 1304corresponds to a frontal scan of the center area of the left breast in adirection close to a lateral-to-medial direction.

FIG. 14 illustrates a single thick-slice image 1401, which correspondsto the thick-slice image 1008 f when the cursor is clicked at thelocation indicated in FIG. 10. It is to be appreciated that the menu bar1006 is preferably displayed below all images but is omitted in this andsubsequent figures for clarity. FIG. 14 further illustrates planarultrasound images 1406 and 1408 corresponding respectively to the planeindicators 1402 and 1404, which intersect at the current cursorlocation.

FIG. 15 illustrates a bilateral comparison array 1502 of thick-sliceimages that is accessed by selection of the bilateral comparison controlbutton 1108, comprising members of an LMLO thick-slice image array aspositionally paired with corresponding members of an RMLO thick-sliceimage array, wherein the slab-like subvolumes of the left breastcorresponding to the LMLO thick-slice image array have an at leastgeneral positionwise association with the slab-like subvolumes of theright breast corresponding to the RMLO thick-slice image array. A bodymarker icon 1504 illustrates the scanning orientations and otherscanning parameters associated with each of the volumetric scans.

FIG. 16 illustrates an expanded bilateral comparison view 1602 of thefourth thick-slice image pair of the bilateral comparison array 1502,which is displayed to when either of those fourth thick-slice images isclicked by the viewer on the display of FIG. 15. A body marker icon 1604includes thick-slice depth markers 1606 showing the location of thefourth thick-slice subvolume within each of the left and right breasts.Nipple locations are also indicated on the body marker icon 1602.

Notably, it is not required that the associations between slab-likesubvolumes of the left and right breasts be precise for the preferredembodiments of FIGS. 15-16. The opposing breasts can be of differentsizes and there can be many incidental variations between the ways theywere scanned. Nevertheless, it has been found highly useful to presentthick-slice image data in bilateral comparison formats such as those ofFIGS. 15-16. For example, breast symmetry is readily analyzed.

FIG. 17 illustrates an array of thick-slice images 1702, two planarimages 1704 a-b corresponding to a current cursor position 1708 on aselected thick-slice image, a body marker icon 1710, nipple markers1706, and a frontal breast icon 1712 according to a preferredembodiment. The nipple markers 1706 can be placed on the thick-sliceimages according to any of (i) a manually-entered nipple positionprovided with the associated volumetric ultrasound scan, (ii) acomputer-derived nipple position automatically generated from theassociated volumetric ultrasound scan, (iii) a computer-derived nippleposition automatically generated based on manual placement of a physicalnipple token for the associated volumetric ultrasound scan, and (iv) aviewer-determined position for the nipple marker. Physical nipple tokencan refer to a marker placed on the skin of the breast at the nipplelocation that is at least partially transparent to ultrasound but thatalso provides a degree of obscuration sufficient for automaticidentification of its presence. Examples can include small siliconetoroids, optionally with specks of metal therein, or any of a variety ofother objects that can have similar effects. Physical nipple token canalternatively refer to a such a marker placed on the ultrasound scanningdevice itself, e.g., on one of the compression plates, at the nipplelocation.

Frontal breast icon 1712 comprises a cursor position indicator 1716variably disposed thereon in a manner that reflects a relative positionbetween the cursor 1708 and the nipple marker 1706 on the selectedthick-slice image. Preferably, the frontal breast icon 1712 has a layoutat least roughly resembling a clock face, and the cursor positionindicator 1716 is positioned relative to the center of that clock faceto reflect both (i) the distance “D” between the cursor 1708 and thenipple marker 1706, and (ii) the direction of the cursor 1708 from thenipple marker 1706 on the display (e.g., about 1:00 in the example ofFIG. 17). The location of the cursor position indicator 1716 dynamicallymoves on the clock face as the cursor 1708 is moved around thethick-slice image. The combined display of the frontal breast icon 1712and the body marker icon 1710 facilitates quick, intuitive comprehensionof the physical and positional relevance of the images being displayed.Frontal breast icon 1712 further comprises a text portion 1714numerically indicating (i) the distance “D,” and (ii) the depth of thecurrently selected thick-slice image from the compressed surface acrosswhich the ultrasound probe was swept.

FIG. 18 illustrates a thick-slice image 1802, two planar images 1804 a-bcorresponding to a current cursor position on the thick-slice image, abody marker icon 1810, nipple markers 1806, a plurality of bookmarks1822, 1824, and 1826, and a frontal breast icon 1812. According to apreferred embodiment, the bookmarks are projected onto correspondinglocations of the currently displayed planar images 1804 a-b, ifapplicable, under an assumption that the bookmark spot is volumetricallyin the middle plane of the slab-like subvolume corresponding to thethick-slice image. Accordingly, FIG. 18 illustrates correspondingbookmarks 1822′ and 1824′ on the superior-inferior planar image 1804 b,because the bookmarks 1822 and 1824 lie along the vertical planeindicator 1825 passing through the current cursor location. Themedial-lateral planar image 1804 a only shows a corresponding bookmark1822″ because only the bookmark 1822 lies along the horizontal planeindicator 1827. Since neither plane indicator 1825 or 1827 intersectsthe bookmark 1826, there is no corresponding bookmark on the planarimages 1804 a-b for that bookmark.

The presence of all of the bookmarks can be toggled on and off bypressing the marker display button 1104. The marker navigation buttons1106 allow the viewer to perform bookmark-centric navigation wherein,upon selection, the cursor is moved to a next bookmark (forward) orprior bookmark (backward), and the corresponding planar images areinstantly displayed. As a default setting, navigation among thebookmarks is ordered in the same order as the bookmarks were entered bythe viewer, although the scope of the preferred embodiments is not solimited. In the example of FIG. 18, the viewer has just pressed the oneof the marker navigation buttons and has landed at the bookmark 1822.Notably, as indicated by the cursor position indicator 1816, the frontalbreast icon 1812 keeps up automatically with the current cursorposition, which in FIG. 18 is about 3 cm from the nipple marker locationat a clock angle of roughly 4:00. The nipple markers and bookmarks canhave any of a variety of shapes, sizes, colors, etc. without departingfrom the scope of the preferred embodiments.

FIG. 19 illustrates an array of thick-slice images 1902 with nipplemarkers 1906 that have been shifted by the viewer (using aclick-and-drag method, for example). Although not necessarily warrantedin this example (because the original position appears accurate based onnipple shadow positions), it may be desirable for the viewer to move thenipple marker location based on their observations, or on otherextrinsic information. The position of the cursor 1908 relative to thenipple marker 1906 having shifted, the position of the cursor positionindicator 1916 automatically shifts on the clock face of the frontalbreast icon from 1916-old to 1916-new (e.g., from about 0.5 cm at 12:00to about 3 cm at 4:00).

FIG. 20 illustrates an array of thick-slice images 2002 with bookmarks2010, 2011, 2012, and 2013 placed thereon, for illustrating amulti-slice bookmark-centric navigation process according to a preferredembodiment. By the viewer clicking on the forward marker navigationbutton 1106, the cursor is instantly taken to the next bookmark, andcorresponding planar images (not shown) are displayed.

Generally speaking, as in the example of FIG. 20, there will often bebookmarks on several of the thick-slice images. Convenient navigationanalogous to that shown in FIG. 20 is provided when only one of thethick-slice images is displayed at a time (see, e.g., FIG. 14, supra).In particular, when only a single thick-slice image is being shown andone of the marker navigation buttons 1106 is pressed, the currentthick-slice image is replaced (if applicable) with a next thick-sliceimage corresponding to a next bookmark, and the cursor is placed at thenext bookmark in that thick-slice image with corresponding planar viewsbeing displayed. Rapid navigation among bookmarks is thereby achieved.

In another preferred embodiment, similar navigation capabilities areprovided among CAD detections, i.e., by the viewer clicking on a CADnavigation button, the cursor is instantly taken to the next CAD markerlocation, and corresponding planar images are displayed. Among otheradvantages, bookmark-centric and/or CAD-centric navigation according tothe preferred embodiments can substantially reduce the time needed toexamine a case and increase radiologist productivity.

FIG. 21 illustrates breast ultrasound volume processing and displayaccording a preferred embodiment. At step 2102, nipple position isobtained either manually or in an automated manner relative to anacquired breast volume that is preferably chestwardly-compressed forhead-on scanning. At step 2104, one or more thick-slice ultrasoundimages is displayed. At step 2106, nipple markers are shown on thethick-slice image(s), the nipple marker positions representing aprojection of the nipple location thereupon. At step 2108, the currentcursor position relative to the displayed nipple marker position iscommunicated on a clock face style icon. At step 2110, the viewer isallowed to change the nipple marker position relative to the breastvolume through direct interaction on thick-slice image(s).

FIG. 22 illustrates breast ultrasound volume processing and displayaccording a preferred embodiment. At step 2202, bookmarks are added viabookmarking commands, e.g., through a right-click and drop-down menustyle command upon a thick-slice image or a planar image. At step 2204,that bookmark location is associated with its corresponding locationwithin the 3D breast volume. At step 2206, that bookmark is projectedonto all relevant displayed thick-slice and planar ultrasound images asrequired to properly reflect its position in the 3D breast volume. If amarker navigation command is received at step 2208, then the displayautomatically navigates to a next bookmark location and shows theappropriate thick-slice image and corresponding planar images at step2210.

FIG. 23 illustrates a bilateral comparison array 2302 of thick-sliceimages that is easily navigated to by selection of the bilateralcomparison control button 1108, supra, comprising members of an LAP(left anterior-posterior) thick-slice image array as positionally pairedwith corresponding members of an RAP (right anterior-posterior)thick-slice image array, wherein the slab-like subvolumes of the leftbreast corresponding to the LAP thick-slice image array have an at leastgeneral positionwise association with the slab-like subvolumes of theright breast corresponding to the RAP thick-slice image array. A bodymarker icon 2304 illustrates the scanning orientations for each breastvolume.

FIG. 24 illustrates examples of a virtual probe reconstruction (VPR)plane “S” around a point “P” within a breast volume 2402 according to apreferred embodiment. The viewer is provided with a pointing device,which can be the regular mouse in a particular mode, or which can be aseparate joystick or similar control. With at least one thick-sliceimage and at least one planar image being displayed, the viewer caninvoke a VPR command for the present cursor position. This causes thecursor to freeze at the present location “P” within the breast volume,wherein the viewer can then change the orientation of the plane “S”corresponding to the displayed planar image from a normal “vertical”position within the breast volume, see FIG. 24 at (i), to any of avariety of different orientations under control of the pointing device.For example, as indicated in FIG. 24, there is provided a rollcapability, see FIG. 24 at (ii), a yaw capability, see FIG. 24 at (iii),and combinations of roll and yaw, see FIG. 24 at (iv).

FIG. 25 illustrates a full-breast composite thick-slice image 2502,corresponding planar images 2504 a-b, a body marker icon 2510, and afrontal breast icon 2512 according to a preferred embodiment. Compositethick-slice image 2502 is preferably a CAD-enhanced expression of thesonographic properties of substantially the entire breast volume, i.e.,all of the tissue imaged by the volumetric ultrasound scans. Any of avariety of CAD algorithms can be used such as those discussed U.S. Pat.No. 6,317,617, supra, and those described in the commonly assigned WO03/101303 A1, supra. The lesions can then be enhanced according to theirlikelihood of malignancy (or other metric of interest) on the compositethick-slice image 2502. The composite thick-slice image 2502 can serveas a useful “guide” or “road map” for viewing the planar ultrasoundimages and the other thick-slice images, and can optionally be providedwith explicit CAD markings near the enhanced lesion locations.

FIG. 26 illustrates a display 2602 comprising a volume-rendered breastultrasound volume 2604 with surface-rendered computer-assisted diagnosis(CAD) detections 2606 therein according to a preferred embodiment. Athree-dimensional nipple marker 2608 is provided to properly orient theviewer in visualizing the breast volume. In one preferred embodiment,the volume-rendered breast ultrasound volume 2604 is rotated in acine-like fashion, as indicated by the sequence A-D in FIG. 26.

Whereas many alterations and modifications of the present invention willno doubt become apparent to a person of ordinary skill in the art afterhaving read the foregoing description, it is to be understood that theparticular embodiments shown and described by way of illustration are inno way intended to be considered limiting. By way of example, althoughprimarily described supra in the context of ultrasound imaging, it is tobe appreciated that data from other full-field breast imaging modalities(e.g., MRI, CT, PET) can be advantageously processed and displayedaccording to one or more of the described preferred embodiments. One ormore of the displays described herein is similar to SOMOGRAM™ displaysprovided by U-Systems, Inc. of San Jose, Calif. By way of furtherexample, although described supra as being volumetrically segregated,the coronal slab-like subvolumes from which the coronal thick-sliceimages are computed can be partially overlapping, which can be useful indealing with lesions that would otherwise straddle the borders of thesubvolumes. By way of even further example, although most nipple markersare described in the preferred embodiments supra in the context ofcoronal thick-slice images, in other preferred embodiments the nipplemarkers are shown on the MLO, CC, and other thick-slice image views.

By way of further example, it is to be appreciated that substantiallyparallel to a coronal plane is used herein to generally reflect thepractical realities of situations such as head-on scanning of thebreast, and that there may be some deviation from the plane of the chestwall. For example, for a particular patient having highly pendulousbreasts it might be found most optimal to compress the breast at somesmall angle, such as 15 degrees, away from the plane of the chest wall.In this case, slab-like subvolumes that are taken parallel to the planeof compression would still be considered substantially parallel to thecoronal plane.

By way of still further example, in alternative preferred embodimentsthe coronal slab-like subvolumes described supra can be replaced bythin-slice coronal images, i.e. thin-slice planar ultrasound imagesalong planes substantially parallel to a coronal plane. This can beparticularly useful in a follow-up diagnosis setting in which finedetails are desired for viewing. By way of still further example, inanother alternative preferred embodiment, the clinician is given theability to interchangeably switch among, or pick-and-choose between,displaying the coronal slab-like subvolumes and the thin-slice coronalimages. Therefore, reference to the details of the preferred embodimentsare not intended to limit their scope, which is limited only by thescope of the claims set forth below.

FIG. 27 illustrates a perspective view of a full-field breast ultrasound(FFBU) scanning apparatus 2702 according to a preferred embodiment,comprising a frame 2704 that may contain an ultrasound processor, amovable support arm 2706, a compression/scanning assembly 2708 connectedto the support arm 2706 via a ball-and-socket connector 2712, and amonitor 2710 connected to the support arm 2706 at a joint 2714.Preferably, the support arm 2706 is configured and adapted such that thecompression/scanning assembly 2708 is either (i) neutrally buoyant inspace, or (ii) has a light net downward weight (e.g., 2-3 pounds) forbreast compression, while allowing for easy user manipulation. Accordingto a preferred embodiment, the compression/scanning assembly 2708comprises an at least partially conformable membrane 2718 in asubstantially taut state, the membrane 2718 having a bottom surfacecontacting the breast while a transducer is swept across a top surfacethereof to scan the breast. Optionally, the support arm 2706 maycomprise potentiometers (not shown) to allow position and orientationsensing for the compression/scanning assembly 2708, or other types ofposition and orientation sensing (e.g., gyroscopic, magnetic, optical)can be used. By way of example and not by way of limitation, a miniBIRD®3D position sensor from Ascension Technologies can be used to determinethe position and orientation of the compression/scanning assembly 2708on a per-frame basis.

Within frame 2704 may be provided a fully functional ultrasound enginefor driving an ultrasound transducer and generating volumetric breastultrasound data from the scans in conjunction with the associatedposition and orientation information. The volumetric scan data can betransferred to another computer system for further processing using anyof a variety of data transfer methods known in the art. A generalpurpose computer, which can be implemented on the same computer as theultrasound engine, is also provided for general user interfacing andsystem control. The general purpose computer can be a self-containedstand-alone unit, or can be remotely controlled, configured, and/ormonitored by a remote station connected across a network.

The compression/scanning assembly 2708 is preferably a substantiallyself-contained, pod-like module that can be grasped by the hands of auser and manipulated to compress the breast in a generally chestwarddirection. By generally chestward, it is meant that membrane 2718 of thecompression/scanning assembly 2708 urges the breast surface toward thechest wall of the patient while the membrane is an angle of 45 degreesor less from a coronal plane. It has been found that, generallyspeaking, the breasts of supine or reclining women can have manydifferent tendencies depending on the anatomy of the woman. For example,for first fully supine woman the breast may droop upward toward theshoulder, while for a second fully supine woman the breast may droopdownward toward the abdomen or inward toward the sternum. For thesebreasts it may be desirable to tilt the scanning surface somewhatrelative to the coronal plane, obtaining a scan of the breast whilepushing the breast at least partially sideways toward the theoreticalcenter of the breast and while also pushing it inward toward the chestwall.

Notably, the scope of the preferred embodiments is not limited to theabove-referenced angles relative to the coronal plane. In otherpreferred embodiments any of a variety of different angles andorientations may be used, depending on the circumstances.

FIG. 28 illustrates a diagram of head-on breast ultrasound scanningaccording to a preferred embodiment, in which a breast 2802 of a patient2804 is scanned using the compression/scanning assembly 2708 of FIG. 12,supra. More generally any similar assembly having a substantially planarscanning surface that is rigid or semi-rigid as compared to the generalsoftness of a breast can be used. For some clinical settings and/orpatient groups, it is often considered sufficient to use a singlehead-on scan to volumetrically image a dense-disk region 2212 of thebreast, the compressive surface being substantially parallel to thecoronal plane and chestwardly pressed against the breast.

In other clinical settings and/or for other patient groups, it is oftendesired to more thoroughly scan the breast by obtaining ancillarycompressive scans at one or more off-coronal angles. However, accordingto a preferred embodiment, at least some degree of systemization and/orstandardization is maintained by using lateral frontal, medial frontal,inferior frontal, and/or superior frontal compression and scanningorientations as described herein. In one preferred embodiment, the imagevolumes acquired from the ancillary compressive scans are used tosupplement the image volume acquired from the head-on scan. In anotherembodiment, the single head-on scans are omitted and only the imagevolumes acquired from the ancillary compressive scans are used.

FIG. 29 illustrates a diagram of lateral frontal breast ultrasoundscanning according to a preferred embodiment, in which thecompression/scanning assembly 2708 is manipulated to image a lateralfrontal region 2914. Preferably, in a positioning process preceding theprobe sweep, one side of the compressive surface is pinned adjacent tothe outer edge of the breast (near the line C-C′ in FIG. 29) and thenthe compressive surface is “rolled” toward the medial side of thebreast, until a position is reached in which the compressive surfacewould lift away from C-C′ if the rolling continued. This has been foundto allow capturing of a relatively large lateral frontal region 2914that usually includes the nipple, while also minimizing small airpockets, bubbles, etc. that can degrade image quality.

FIG. 30 illustrates a diagram of medial frontal breast ultrasoundscanning according to a preferred embodiment, in which thecompression/scanning assembly 2708 is manipulated to image a medialfrontal region 3016. In a manner analogous to the lateral frontal scan,one side of the compressive surface is preferably pinned adjacent to themedial edge of the breast (near the line C-C′ in FIG. 30) and then thecompressive surface is “rolled” toward the outer side of the breast,until a position is reached in which the compressive surface would liftaway from C-C′ if the rolling continued.

FIG. 31 illustrates a diagram of inferior frontal breast ultrasoundscanning according to a preferred embodiment, in which thecompression/scanning assembly 2708 is manipulated to image an inferiorfrontal region 3118. In a manner analogous to the lateral and medialfrontal scans, one side of the compressive surface is pinned at theinferior mammary fold (IMF, near the line C-C′ in FIG. 31) and then thecompressive surface is “rolled” upward toward the superior surface ofthe breast, until a position is reached in which the compressive surfacewould lift away from C-C′ if the rolling continued. FIG. 32 illustratesa diagram of superior frontal breast ultrasound scanning according to apreferred embodiment, in which the compression/scanning assembly 2708 ismanipulated to image a superior frontal region 3220.

In one embodiment, the number and selection of ancillary compressivescans is determined according to a size category of the breast. For asmall breast, the lateral frontal scan (FIG. 29) and the medial frontalscan (FIG. 30) can suffice to ultrasonically image the clinicallyrelevant tissues. For a medium sized breast, the inferior frontal scan(FIG. 31) is acquired in addition to the lateral and medial frontalscans to facilitate sufficient imaging of the clinically relevanttissues. For a large-sized breast, the superior frontal scan (FIG. 32)is acquired in addition to the lateral, medial, and inferior scans forcapturing the clinically relevant tissues. Advantageously, a set ofgenerally standard and comparable ultrasound image volumes is acquiredaccording to the size of the breast for facilitating year-over-yearcomparisons, comparisons of similarly-sized breasts, and/or a variety ofother useful purposes.

Automated navigation between a first ultrasonic volume of a breastacquired during a first volumetric scan thereof and a second ultrasonicvolume of the same breast taken during a second volumetric scan thereofis now described. FIG. 33 illustrates one example of the overall goal ofthe method, showing a first coronal thick-slice image 3302 derived froma first ultrasound volume that may have been acquired according to FIG.28, that is, a direct head-on scan. A second coronal thick-slice image3304 is derived from a second ultrasound volume that may have beenacquired according to FIG. 32, that is, a superior frontal scan.Alternatively, one or both of these images may be a planar ultrasoundslice, the method proceeding in substantially the same way for planarslices as for thick-slice images. Generally speaking, the ultrasounddisplay will segregate the images corresponding to the first and secondultrasonic volumes such that the viewer is aware of the distinctionbetween the two. The user has selected a source region of interest (ROI)in the first image 3302, and according to a prefefred embodiment,automatic navigation is provided by computing a corresponding location(termed a destination ROI) in the second thick-slice image andhighlighting that location, allowing the user to quickly take a“different look” at the region of interest. The automated navigation ispreferably nipple-centric, i.e., the mapping between volumes is based ona position of the source ROI relative to the nipple in the firstultrasonic volume, with the destination ROI being identified as thatlocation in the second subvolume having the same relationship with thenipple location as it appears in the second subvolume. Moreparticularly, the relative positions are based on distance and directionfrom the nipple when the ROI is projected onto a coronally orientedplane going through the nipple location. The described method has beenfound to yield sufficiently accurate results without requiring intensiveinternal feature-based volume mappings, while also being flexible forthe large variety of different scan orientations that might be used.

Nipple locations 3308 and 3310 in the first and second ultrasonicvolumes are identified either automatically or manually according to anyof the above-described methods. Notably, the nipple is positioneddirectly in the middle for the head-on scan thick-slice image 3302 whileit is skewed toward the bottom for the superior frontal scan thick-sliceimage 3304. When the ROI 3306 is selected (termed a source ROI herein),it is mapped from the thick-slice image 3302 into the correspondingfirst ultrasonic volume, according to the known position of theassociated slab-like subvolume within the first ultrasonic volume. Thesource ROI is then mapped from within the first ultrasonic volume into acorresponding destination ROI within the second ultrasonic volume of thebreast. The destination ROI is then mapped onto the second image 3304according to the known position of the second thick-slice image withinthe second ultrasonic volume. The second image is displayed to theviewer with the position of the destination ROI therein beinghighlighted (see FIG. 37).

With reference herein to FIGS. 34-38, in one preferred embodiment, themapping from the source ROI 3306 within the first ultrasonic volume 3402into the corresponding destination ROI 3604 (see FIG. 36) within thesecond ultrasonic volume 3602 first comprises identifying a nipplelocation 3308 and 3310 of the breast in each of the first and secondultrasonic volumes 3306 and 3604. A projected location of the source ROI3306 onto a first coronal reference plane 3404 passing through thenipple location within the first ultrasonic volume is then identified(see FIG. 34). A Cartesian offset (by Cartesian, it is meant that theoffset is within a plane and can be identified by two coordinates suchas Δx, Δy or, in this case, a radius r and angle α; the term “in-planeoffset” may alternatively be used) between the projected source ROIlocation and the nipple location on the first coronal reference plane3404 is then determined.

With reference to FIG. 35, that Cartesian offset (r,α) is thentransferred to a second coronal reference plane 3502 to identify atransferred offset point 3504 thereon, the second coronal referenceplane 3502 passing through the nipple location within the secondultrasonic volume 3602. The transferred offset point 3504 is thenbackprojected (see FIG. 36) from the second coronal reference plane 3502into the second ultrasonic volume 3604. The distance “d” in thechestward direction from the nipple is known (see FIG. 34) by virtue ofthe known thick-slice that was clicked upon, and applied in thebackprojection in FIG. 36.

In another preferred embodiment, with reference to FIG. 38,accommodations are made for compression of the breast along ananti-coronal plane (i.e., along a plane perpendicular to the coronalplane, which would include CC, MLO, and LAT, for example) during one orboth of the volumetric scans. In particular, where the breast was socompressed during the first scan or the second scan (but not both), thetransferred point 3804 on the second coronal reference plane 3802 ismodified according to an elastic mapping (38024→3806) between a coronalprojection 3802 of the anti-coronally-compressed breast onto a coronalprojection 3806 of the non-anti-coronally-compressed breast. The “clockposition” of the transferred point changes due to an expansion of thebreast along the vertical direction in FIG. 38 to a different clockposition 3808. The elastic mapping is determined at least in partaccording to a measured compression force and a distance betweencompression plates during breast compression along the anti-coronalplane. In one preferred embodiment, the breast can be modeled as athree-dimensional object having known compressibility, and so thecompressed outline (as projected onto the coronal plane) can bere-expanded outward where the compression force and the plate distanceare known.

If the breast was so compressed for both volumetric scans, the breastbeing compressed along a first anti-coronal plane during the firstvolumetric scan thereof and compressed along a second anti-coronal planeduring the second volumetric scan thereof, the transferred point on thesecond coronal reference plane is modified according to an elasticmapping between a coronal projection of the breast as compressed alongthe first anti-coronal plane and a coronal projection of the breast ascompressed along the second anti-coronal plane.

Whereas many alterations and modifications of the present invention willno doubt become apparent to a person of ordinary skill in the art afterhaving read the foregoing description, it is to be understood that theparticular embodiments shown and described by way of illustration are inno way intended to be considered limiting. By way of example, there canbe many different ways of displaying the first ultrasound volume (and,when selected, the source ROI thereon) and the second ultrasound volume(including the destination ROI thereon) without departing from the scopeof the preferred embodiments. For example, two side-by-side displaymonitors can be provided that are each similar to FIG. 18, supra, thefirst monitor showing the breast as scanned in Year N, and the secondmonitor showing the breast as scanned from Year N+1. The user can selecta particular location of interest in the Year N breast volume on thefirst monitor, and then invoke a “map” command or similar input.Responsive thereto, the second display would automatically navigate tothe appropriate thick-slice and planar images that intersect thatselected location in the Year N+1 breast volume. Alternatively, insteadof showing Year N and Year N+1 volumes simultaneously on two differentmonitors, a single monitor can be used to alternate between displayingYear N and Year N+1. Thus, while Year N is being displayed, the userwould select a location of interest in the Year N breast volume and theninvoke the “map” command or similar input. Responsive thereto, thedisplay would automatically replace the Year N volume with the Year N+1volume, with the corresponding location in the Year N+1 volume beingautomatically navigated to and highlighted. When viewing for temporalcomparison, this alternative method provides a sort of “time travel” onthe user display, because the user is staying in the same location butis being thrust forward or backward in time. When viewing foralternative views taken on the same date (e.g., navigating between alateral frontal scan and a medial frontal scan of a breast taken duringthe same session), this alternative method provides a sort of“hyperspace” on the user display, because the user is staying at thesame general point in time but is being instantly transported todifferent views of the ROI. In one illustration, when a suspiciouslocation is occluded (e.g., by shadowing) in the lateral frontal scan,the user can use the above-described methods to instantly view themedial frontal scan at that suspicious location for a clearer view.Therefore, reference to the details of the preferred embodiments are notintended to limit their scope, which is limited only by the scope of theclaims set forth below.

1. A computer-implemented method for facilitating review of dataassociated with different volumetric ultrasonic scans of a same breast,the breast having been compressed in a generally chestward direction bya compressive surface for each of the different volumetric ultrasonicscans, the compressive surface encompassing a nipple of the breast,comprising: receiving, at one or more computer processing units, firstand second data volumes derived respectively from the differentvolumetric ultrasound scans; displaying a first image representative ofvalues at a first plurality of known locations within said first datavolume; receiving, at the one or more computer processing units, aselection of a first location within the first data volume relative tosaid first displayed image; operating the one or more processing unitsto identify a second location within the second data volume having asimilar spatial disposition relative to the nipple and the compressivesurface as said first location within said first volume, whereby saidsecond location at least roughly corresponds to a same locality oftissue within the breast as said first location; and displaying a secondimage representative of values at a second plurality of known locationswithin said second data volume including said second location, saidsecond image comprising a visible mark denoting said second locationthereon.
 2. The computer-implemented method of claim 1, furthercomprising receiving a manual identification of a nipple location ineach of said first and second data volumes.
 3. The computer-implementedmethod of claim 1, wherein said first images comprises one of a planarimage and a thick-slice image derived from the first data volume.
 4. Thecomputer-implemented method of claim 1, wherein said differentvolumetric ultrasound scans of the breast were acquiredcontemporaneously and comprise different ones of the group consistingof: lateral frontal view, medial frontal view, inferior frontal view,and superior frontal view.
 5. The computer-implemented method of claim1, wherein said operating the one or more processing units to identifythe second location comprises determining a Cartesian offset of saidfirst location relative to the nipple in a coronal reference plane andidentifying said second location in the second data volume to have asimilar Cartesian offset relative to the nipple in the coronal referenceplane.
 6. The computer-implemented method of claim 5, wherein saidoperating the one or more processing units to identify the secondlocation comprises determining a depth of said first location relativeto the compressive surface in the first data volume and identifying saidsecond location in the second data volume to have a similar depthrelative to the compressive surface.
 7. The computer-implemented methodof claim 1, wherein said different volumetric ultrasound scans of thebreast comprise identical views acquired at substantially differenttimes.
 8. A computer-implemented method for facilitating review of dataassociated with different volumetric ultrasonic scans of a same breast,comprising: receiving, at one or more computer processing units, firstand second data volumes derived respectively from the differentvolumetric ultrasound scans; displaying on a display device a firstimage representative of values at a first plurality of known locationswithin said first data volume; receiving, at the one or more computerprocessing units, a selection of a first location within the first datavolume relative to said first displayed image; operating the one or moreprocessing units to identify a second location within the second datavolume at least roughly corresponding to a same locality of tissuewithin the breast as said first location; and replacing said first imageon said display device with a second image representative of values at asecond plurality of known locations within said second data volumeincluding said second location, said second image comprising a visiblemark denoting said second location thereon.
 9. The computer-implementedmethod of claim 8, the breast having been compressed in a generallychestward direction by a compressive surface for each of the differentvolumetric ultrasonic scans, the compressive surface encompassing anipple of the breast, wherein said second location within the seconddata volume is identified as that which has a similar spatialdisposition relative to the nipple and the compressive sur face as saidfirst location within said first volume.
 10. The computer-implementedmethod of claim 9, wherein said operating the one or more processingunits to identify the second location comprises determining a Cartesianoffset of said first location relative to the nipple in a coronalreference plane and identifying said second location in the second datavolume to have a similar Cartesian offset relative to the nipple in thecoronal reference plane.
 11. The computer-implemented method of claim10, wherein said operating the one or more processing units to identifythe second location comprises determining a depth of said first locationrelative to the compressive surface in the first data volume andidentifying said second location in the second data volume to have asimilar depth relative to the compressive surface.
 12. Thecomputer-implemented method of claim 8, further comprising receiving amanual identification of a nipple location in each of said first andsecond data volumes.
 13. The computer-implemented method of claim 8,wherein said first images comprises one of a planar image and athick-slice image derived from the first data volume.
 14. Thecomputer-implemented method of claim 8, wherein said differentvolumetric ultrasound scans of the breast were acquiredcontemporaneously and comprise different ones of the group consistingof: lateral frontal view, medial frontal view, inferior frontal view,and superior frontal view.
 15. A method for automated navigation ofbreast ultrasound information, comprising: displaying a first imagederived from a first ultrasonic volume of a breast acquired during afirst volumetric scan thereof, said first image comprising one of (i) athick-slice image representing said first ultrasonic volume within aslab-like subvolume thereof, and (ii) a planar image representing saidfirst ultrasonic volume along a plane therethrough; receiving a userselection of a source region of interest (ROI) in said first image;mapping said source ROI from said first image into said first ultrasonicvolume according to a known position of the slab-like subvolume or planeassociated with the first image within the first ultrasonic volume;mapping said source ROI within said first ultrasonic volume into acorresponding destination ROI within a second ultrasonic volume of thebreast acquired during a second volumetric scan thereof taken at adifferent position or orientation relative to said first volumetricscan; mapping said destination ROI within said second ultrasonic volumeonto a second image, said second image comprising one of (i) athick-slice image representing said second ultrasonic volume within aslab-like subvolume thereof, and (ii) a planar image representing saidsecond ultrasonic volume along a plane therethrough, said mapping beingin accordance with a known position of said slab-like subvolume or planewithin the second ultrasonic volume; displaying said second image to theviewer; and highlighting said destination ROI on said second image. 16.The method of claim 15, said mapping said source ROI within said firstultrasonic volume into the corresponding destination ROI within thesecond ultrasonic volume comprising: identifying a nipple location ofthe breast in each of said first and second ultrasonic volumes thereof;identifying a projected location of the source ROI onto a first coronalreference plane passing through the nipple location within the firstultrasonic volume; determining a Cartesian offset between said projectedsource ROI location and said nipple location on said first coronalreference plane; transferring said Cartesian offset to a second coronalreference plane to identify a transferred offset point thereon, saidsecond coronal reference plane passing through the nipple locationwithin the second ultrasonic volume; and backprojecting said transferredoffset point from said second coronal reference plane into said secondultrasonic volume.
 17. The method of claim 16, wherein said breast iscompressed along an anti-coronal plane during one of said first orsecond volumetric scans thereof and not compressed along an anti-coronalplane during the other volumetric scan thereof, further comprisingmodifying said transferred point on said second coronal reference planeaccording to an elastic mapping between a coronal projection of theanti-coronally-compressed breast onto a coronal projection of thenon-anti-coronally-compressed breast.
 18. The method of claim 17,wherein said elastic mapping is determined at least in part according toa measured compression force along the anti-coronal plane and a distancebetween compression plates during breast compression.
 19. The method ofclaim 17, wherein said breast is compressed along a first anti-coronalplane during said first volumetric scan thereof and compressed along asecond anti-coronal plane during said second volumetric scan thereof,further comprising modifying said transferred point on said secondcoronal reference plane according to an elastic mapping between acoronal projection of the breast as compressed along the firstanti-coronal plane and a coronal projection of the breast as compressedalong the second anti-coronal plane.
 20. The method of claim 19, whereinsaid elastic mapping is determined at least in part according to ameasured compression force along the anti-coronal plane and a distancebetween compression plates during breast compression.